JP2002214521A - Range-finding device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a range-finding device for an automatic focusing camera capable of performing exact focusing even in the case of a low-contrast landscape such as the sky or a mountain and a bright scene. SOLUTION: Two images of an object 2 are received by a pair of sensor arrays 3a and 3b having parallax in order to detect a distance. The difference of output between a pair of sensor arrays 3a and 3b is compared with a specified value by a CPU 10 so as to decide the level of reliability in the detection of the distance by the two images. The brightness of the object image is detected, and the specified value is changed by the CPU 10 according to the detected output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus used for focusing a camera, and more particularly to an improvement of a so-called passive type distance measuring apparatus having a sensor array and utilizing an image signal of a subject. Things.

[0002]

2. Description of the Related Art In general, in a so-called passive AF (autofocus) type distance measuring device having a sensor array and utilizing an image signal of a subject, when a clear contrast is present in an image, it is sufficient. Although the distance measurement accuracy can be obtained, on the contrary, when the contrast of the subject image is low, it becomes difficult to detect the distance. In particular, the sky, landscape, and the like are subjects to which the passive AF method is weak because the contrast changes gradually.

[0003] However, the blue sky and the gentle mountains
It is a scene that invites you to travel and is often taken up as the subject of photography. In order to correctly measure the distance of such a subject, for example, as described in Japanese Patent Application Laid-Open No. 9-325262 by the present applicant, a method of searching for a portion having as much contrast as possible in a photographic screen is known. Have been.

[0004]

However, as shown in FIG. 10, the sky and clouds, the shadows of mountains, and the like have only very gentle shading. For this reason, if distance detection is performed in the same process as a normal scene such as a person or a building, it is often impossible to correctly measure the distance.

[0005] In recent years, in a scene where passive AF is weak, a method (hybrid AF, combination AF) using active AF for projecting light for distance measurement is being commercialized. However, in the active mode, there is a limit to the intensity of light to be projected. In an extremely bright scene, the distance measurement light is hard to be erased by being buried in the background light, and a long-distance object is used for the distance measurement. Light did not reach,
Further, the accuracy is deteriorated.

Accordingly, in such a scene, it is preferable to measure the distance by the passive AF as much as possible, and it is necessary to secure the accuracy by avoiding the distance measurement in the active mode as much as possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a camera for an autofocus (AF) capable of performing accurate focusing even in a low-contrast landscape such as the sky or a mountain and a bright scene. It is an object of the present invention to provide a distance measuring device.

[0008]

That is, the present invention provides a pair of sensor arrays for receiving two images of a subject with parallax for distance detection, and a difference in output between the pair of sensor arrays. Determining means for comparing the predetermined values to determine the level of reliability of distance detection based on the two images; brightness detecting means for detecting brightness of the subject image; and output of the brightness detecting means. And a changing means for changing the predetermined value according to the following.

According to another aspect of the present invention, there is provided a pair of sensor arrays for receiving two images of a subject with parallax for detecting a distance, and a sensor in a specific area of at least one of the pair of sensor arrays. Determining means for comparing the output difference with a predetermined value to determine the level of reliability of distance detection using the two images; brightness detecting means for detecting brightness of the subject image; Changing means for changing the predetermined value according to the output of the means.

In the camera distance measuring apparatus according to the present invention,
Two images of the subject are received by a pair of sensor arrays having parallax for distance detection. Then, the difference between the output between the pair of sensor arrays and a predetermined value is compared by a determination unit to determine whether the reliability of distance detection using the two images is high or low. Further, the brightness of the subject image is detected by the brightness detecting means, and the predetermined value is changed by the changing means according to the output of the brightness detecting means.

In the camera distance measuring apparatus according to the present invention, two images of the subject are received by a pair of sensor arrays having parallax for detecting a distance. Then, a sensor output difference of a specific area of at least one of the pair of sensor arrays and a predetermined value are compared by a determination unit to determine whether the reliability of distance detection based on the two images is high or low. Is done. The brightness of the subject image is
The predetermined value is detected by the brightness detecting means, and the predetermined value is changed by the changing means according to the output of the brightness detecting means.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a camera according to an embodiment of the present invention. In the figure,
In order to avoid complication of the drawings, only members related to the present invention are shown, and other components are omitted.

As shown in FIG. 1, the camera according to the present embodiment has a so-called passive type distance measuring device.

That is, this camera is provided with two light receiving lenses 1a and 1b arranged at a distance of a base line length B, and at a focal distance f behind the light receiving lenses 1a and 1b. Sensor arrays 3a and 3b, each of which includes a line sensor for receiving a light beam from the subject 2 that has passed through the first and second light sources 1a and 1b, and a signal (analog) of subject light obtained and photoelectrically converted by the sensor arrays 3a and 3b An A / D converter 4 for converting the signal into a digital signal, and a calculator 5 for receiving the optical signal converted by the A / D converter 4 and performing a predetermined calculation such as calculating an image shift amount. And a CPU 10 which is an arithmetic control means including a one-chip microcomputer for controlling the entire distance measuring device of the camera.

The CPU 10 includes a focus control unit 12 for controlling the operation of the focus lens group 11, and a photometric unit 13.
And a flash light emitting device (hereinafter referred to as a strobe device) 14
, A driver 18 for controlling the projection of light from an infrared light emitting diode (IRED) 17 through a projection lens 16, a steady light removal circuit 19, a release switch 20, and the like. Is connected.

The focus lens group 11 constitutes a part of the photographing lens group, and can move in the optical axis direction for a focusing operation. Then, the focusing control unit 12 performs the focusing lens group 11 based on the distance measurement result by the distance measuring device.
Focusing control means for controlling the movement of the lens, and is composed of an actuator, an encoder and the like.

In the photometric section 13, the brightness of the subject 2 is measured. The strobe device 14 includes a flash light emitting unit such as a xenon tube. The strobe device 14 has a strobe control unit 15 that controls light emission by a strobe light control unit including a strobe light control circuit. Is done.

The IRED 17 projects light with contrast when the object 2 has no contrast. The light emission of the IRED 17 is controlled by the CPU 10 controlling the driving of the driver 18 according to the situation.

The stationary light removing circuit 28 is a circuit that removes a portion of the output photocurrent of the sensor arrays 3a and 3b that is constantly output. The release switch 20 includes a switch (SW) for generating a release signal for starting execution of a photographing operation, and the like.

Further, the A / D converter 4 includes an integration circuit 4a as integration means for integrating the optical image signal, and an integration determination for determining whether or not a strobe light emission operation is necessary at the time of a distance measurement operation. And a determination unit 4b as a means.

The strobe device 14 and the strobe control unit 15 form a strobe light emitting means.

The distance between the two light receiving lenses 1a and 1b and the object 2 is indicated by the symbol L.

Next, a description will be given of a method of calculating the relative position difference between the light patterns of the distance measuring device in the camera having the above-described configuration.

Light patterns are formed on the sensor arrays 3a and 3b as shown by curved patterns 23a and 23b. These light patterns 23a and 23b depend on the luminance distribution of the subject 2 and the relative positional relationship between the two light receiving lenses 1a and 1b.

That is, the sensor array 3a, 3b is determined by the positional difference between the two light receiving lenses 1a, 1b, that is, the base line length B.
The relative position difference x of the distribution of the light patterns 23a and 23b incident on b changes depending on the distance L to the subject 2 (hereinafter referred to as the subject distance) L. In this case, if the focal length f of the two light receiving lenses 1a and 1b, the subject distance L can be obtained by L = B × f / x (1).

Each sensor of the sensor arrays 3a and 3b outputs a current signal according to the amount of incident light.
If the digital signal is converted by the / D conversion unit 4, the image shift amount, that is, the relative position difference x can be calculated by the correlation calculation by the calculation unit 5. In response to this result, the CPU 10 performs an operation based on the above equation (1). Thereby, the subject distance L is obtained.

The above is the basic principle of the triangular distance measuring method in the passive type distance measuring device, and the general structure of the device.

The function of calculating the amount of image shift usually comprises two processes, as will be described later. However, these functions may be incorporated in the CPU 10 as a control program.

When the focus adjustment operation of the camera is performed using such a technique, the CPU 10 controls the operation of the camera, and controls the focus adjustment focus lens 11 and the like which constitute a part of the photographing lens. By appropriately controlling the driving force of an actuator (not shown) such as a driving motor via the unit 12, a camera with a so-called automatic focus adjustment (AF) function can be provided.

In order to calculate the amount of image shift, an operation step for checking how much the image is shifted in units of sensor pitch in the two sensor arrays 3a and 3b, that is, a correlation operation is required. . Then, an operation step of calculating a more accurate deviation amount with a finer resolution, that is, an interpolation operation is required.

Here, a schematic procedure of each process regarding the correlation calculation and the interpolation calculation will be described below.

First, the process of the correlation calculation will be described.

When light having a pattern indicated by reference numeral 23a in FIG. 1 is incident on the sensor array 3a, the magnitude of the output of each of the sensors R _{1 to} R ₆ is as shown in FIG. Distribution. This distribution corresponds to the waveform of the light pattern 23a.

The symbol R shown in FIG. 2 represents the sensor array on the right side of the two sensor arrays 3a and 3b. Similarly, the symbol L shown in the following description represents the sensor array on the left side. Shall be represented. R _{1 to} R ₆ represent the absolute positions of the respective sensors with reference to the optical axes of the light receiving lenses 1a and 1b. In this case, assuming that output signals substantially equal to those of the right sensors R _{1 to} R ₆ can be obtained from the left sensors L _{1 to} L ₆ , the relative position difference x between them is 0.
Becomes Therefore, the required subject distance L is infinity.

When the subject 2 exists at a finite distance,
If they do not exist at infinity,
The relative position difference x of the images incident on the rays 3a, 3b
And the pitch SP between the individual sensors
Left sensor L at a position shifted (shifted) by the number of sensors
As shown in FIG. 3, the sensor output R₁~
R ₆An output signal having a value similar to that of FIG. 2 is obtained.

The value on the vertical axis in FIG.
Sum FF of the difference between the sensor R and the left sensor L _(i)Is given by
Required. FF_(i)= Σ | R_(i)-L_(i)... (2) That is, an arbitrary sensor output of the right sensor R and this
Is subtracted from the sensor output of the left sensor L corresponding to
The result of adding the absolute value for each sensor is FF. here
So, first, R_iTo L_iAnd take its absolute value,
I is changed in a predetermined width, and these are added.

Next, by shifting one of the sensors R _i or L _i by one unit, a difference by performing the same operation. Then, FF _{(i + 1)} can be expressed by the following equation (3). FF _{(i + 1)} = Σ | R _{(i + 1)} −L _(i) | (3) In this manner, the FF can be obtained by sequentially changing the shift amount. And the sum F of the difference between the sensor R and the sensor L
Since the position at which F is the minimum value (Fmin) is considered to be the position where the correspondence is best taken, the shift amount (shift amount) in this case is represented by the symbol S to be shifted in FIG. Is required.

The above is the outline procedure of the process regarding the correlation operation. If the minimum value Fmin of the correlation function is larger than a predetermined level Fmin _0, low degree of coincidence of the images, it can be considered to have low reliability of the distance measurement.

FIG. 3 shows the output distribution of both sensor arrays 3a and 3b, taking into account the value indicated by reference symbol S.
In the same manner as shown in the above, equivalent output is obtained from each sensor on the R side corresponding to the output distribution of each sensor shifted by the shift amount S in each sensor on the L side.

Next, with reference to FIGS. 2, 3 and 5, the process of the interpolation operation will be described.

The actual amount of image shift on the two sensor arrays 3a and 3b is not exactly shifted by the pitch SP of each sensor, and in order to realize an accurate distance measurement operation, it is necessary to use the sensor pitch SP. In addition, it is necessary to detect the image shift amount with fine precision. Thus, an interpolation operation is performed.

In FIG. 2 and FIG.
Represents a part of the sensor output of each sensor constituting the sensor arrays 3a and 3b shown in FIG.

FIG. 5 is a graph in which the outputs of the respective sensors, for which the correlation calculation process has been completed, are shifted by the shift amount S and are then easily compared. In other words, what is indicated by L ₀ ~L ₄ In FIG. 5, to be precise, L that is to be described as _{(S) ~L (S + 4} ), avoiding complication For this reason, the symbol (S) is omitted.

Here, even after being shifted by the shift amount S, the light shifted by the relative position difference x (see FIG. 1) with respect to the R-side sensor enters the L-side sensor. It is assumed that In this case, for example, the light incident on R ₀ and R ₁ is mixed and incident on the sensor L ₁ ,
Similarly, light shifted by the position difference x with respect to the sensor R is sequentially incident on each sensor on the L side. Therefore, it is understood that the sensor outputs (L _{1 to} L ₃ ) on the L side are expressed as shown in the following equations. L ₁ = (1-x) · R ₁ + xR ₀ (4) L ₂ = (1-x) · R ₂ + xR ₁ (5) L ₃ = (1-x) · R ₃ + xR ₂ (6) The above-mentioned Fmin and the values F-1 and F + 1 of the FFs obtained by shifting the shift amount from the Fmin in the plus direction and the minus direction by using the outputs of the sensors R _n and L _n are as follows. It can be expressed as an equation. _{Fmin = Σ | R n -L n} | ... (7) F-1 = Σ | R (n-1) -L n | ... (8) F + 1 = Σ | R (n + 1) -L n | ... (9) Further, using the above equations (4) to (6), (7) to (9)
Expanding the equation, the values Fmin, F-1, and F + 1 are represented by the following (1)
0) can be expressed as shown below.

[0046]

(Equation 1)

The underlined portion in the above equation (10), that is, {| R ₀ −R ₁ | + | R ₁ −R ₂ | + | R ₂ −R ₃ |}. Is expressed as (ΣΔR), this (ΣΔR)
, The above-mentioned displacement amount (position difference) x can be obtained by calculation using the following equation (11).

[0048]

(Equation 2)

The above is the process of the interpolation calculation.

Note that these calculations are performed in the calculation unit 5 in FIG. 1, but are not limited to this. For example, the calculation is performed inside the CPU 10 as calculation control means according to a predetermined program. It may be configured as follows.

FIG. 6 is a flow chart for explaining the operation of the arithmetic processing by the CPU 10.

That is, the CPU 10 first receives the output of each sensor of the sensor arrays 3a and 3b (data reading processing). Thereafter, in step S2, the above-described correlation calculation is performed according to a predetermined program (software). Then, in step S3, a reliability determination is performed.

Here, if the result of the reliability judgment is OK,
The process proceeds to step S4 to perform an interpolation operation. Then, based on the result, in step S5, the extension amount of the focus lens 11 or the like of the photographing lens is calculated.

On the other hand, if the result of the reliability judgment is NG in step S3, the process proceeds to step S6 to issue a warning.

Thereafter, control for focusing adjustment is performed by the focusing control unit 12 and the like.

In the distance measuring apparatus in which the basic operation as described above is performed, a clear light image signal cannot be obtained when the brightness of the subject is insufficient or the subject has a low contrast. This causes a problem that the accuracy of distance measurement is deteriorated.

In such a case, the object 2
The light image of D17 may be projected, and the distance may be detected from the amount of image shift based on the reflected light.

At this time, a circuit (stationary light removing circuit) 28 for removing a portion of the output photocurrent output from the sensor array that is constantly output is operated, and the IRE that emits light in a pulsed manner is operated.
If only the reflected light of D17 is integrated, the signal will not be buried in the sunlight or artificial illumination light in the room, and a more accurate distance measurement can be performed. At a distance where the light of the IRED 17 does not reach, the strobe device 14 similarly emits pulse light,
Distance detection may be performed based on an image based on the reflected light component.

However, when the subject is at a long distance, the IRED
The light and strobe light by the light beam 17 do not arrive, and the reflected light image cannot be detected.

Based on these points, the distance measuring operation according to the embodiment of the present invention will be described with reference to the flowcharts of FIGS.

When the distance measuring operation is started, first, in step S11, integration is performed on a capacitor of each sensor in order to convert a photocurrent corresponding to light incident on each sensor array into a voltage signal. Next, in step S12, the time required until the integration amount reaches a predetermined level is t.
Counted as _INT .

Then, in step S13, it is determined whether or not the integral has reached a predetermined level. Here, if the predetermined level has been reached, the process proceeds to step S15, and if not, the process proceeds to step S14. This is because it takes a long time to integrate when the image is dark, so it is determined in step S14 whether a predetermined time has elapsed. If the predetermined time has not been reached, the process proceeds to step S12,
If the predetermined time has elapsed, the integration is interrupted and step S1 is performed.
Go to 5.

In step S15, the integrated voltage of each sensor is converted as a digital signal by the A / D converter 4 and input to the CPU.

Thereafter, in step S16, the time required for integration is determined. That is, since the integration time t _INT is short in a bright scene and long in a dark scene, the predetermined value t _INT0 is compared with the integration time t _INT to determine the brightness. If it is bright, the process proceeds to step S17, and if it is dark, the process proceeds to step S19. Then, a constant ΔR _{0 for} low contrast determination and a coefficient F for reliability determination
min ₀ is determined in steps S17 and S1 according to the brightness.
8, or set in steps S19 and S20.

In a bright scene, the aperture value FN of the photographing lens
o. May be large and the depth of field is deep, so that even if the focus position control is slightly deviated from that in a dark case, the out-of-focus state does not appear on the photograph. Therefore, even if the contrast of the image is low or the reliability is low (Fmin
Step S so that the distance measurement is successful
ΔR ₁ in step 17 is smaller than ΔR _{2 in} step S19, and Fmin _{1 in} step S18 is larger than Fmin _{2 in} step S20. Is to be assigned.

Next, in step S21, the difference between the maximum value and the minimum value of the sensor data in a predetermined area of the R-side sensor array is set to ΔR. When ΔR is large, it can be determined that the contrast is large, and when ΔR is small, it can be determined that the contrast is low and the distance measurement is not suitable. Therefore, in step S22,
ΔR ₀ and ΔR described above are compared.

[0067] Here, when [Delta] R is less than [Delta] R _0, since the image data obtained in the previous integration unsuitable for range finding, the operation proceeds to step S29, hereinafter re by an active mode with optical projection An integration reset operation is performed to perform integration.

On the other hand, if it is determined in step S22 that the contrast is OK, a correlation operation is performed in step S23. Next, in step S24, the minimum value Fmin of the correlation function obtained in the above step 23,
A predetermined value Fmin ₀ is compared.

Here, the minimum value Fmin is equal to a predetermined value Fmin ₀
If it is larger, it is determined that the coincidence between the two images obtained by the two sensor arrays is low and the image is inappropriate for distance measurement, and the process shifts to step S26. In this step S26, it is determined whether or not it is the active AF. If it is the active AF, the process proceeds to step S27,
Distance measurement (light amount AF) using the light amount reflected from the subject 2 is performed. Thereafter, the process proceeds to step S28. If it is not the active AF, step S29
Move to.

If the predetermined value Fmin ₀ is larger than the minimum value Fmin in step S24, it is determined that Fmin is also OK, and the flow advances to step S25 to perform the above-described interpolation calculation, and the distance is calculated. Is calculated. Then, in step S28, the focus amount is determined.

The above is the distance measurement by the normal passive AF, and the determination level of whether or not distance measurement is possible is switched between a bright case and a dark case. It is possible to detect a distance by a delicate contrast such as a shade of a mountain, and to perform good focusing.

Next, distance measurement in the active mode after step S29 will be described.

When the integration is reset at step S29, the IRED 17 is projected at step S30. Then, in step S31, the above step S
The distance measured by the IRED 17 or the distance measurement using the strobe device 14 is determined based on the magnitude of the reflected light from the subject 2 of the IRED 17 projected at 30.

In the active mode, at the time of light emission control of the light emitting means, as described above, the steady light removing circuit 19 is operated, and the light quantity determination of only the signal based on the signal light purely projected from the camera side is performed. .

That is, the integral amount is determined in step S31. If the result (integral amount) of the pre-emission in step S30 is large, it is determined that the light from the IRED 17 has reached the subject 2, The IRED emission AF from S32 is performed. On the other hand, step S
If the integration amount is small at 31, the process proceeds to step S38, and the distance measurement using the light of the strobe device 14 is performed.

In step S32, the IRED 17 emits light, and in step S33, counting of the number of times of emission (N _IR ) is started. Next, in step S34,
It is determined whether or not the predetermined amount has been integrated. If the predetermined amount has been integrated, the process proceeds to step S15. If the predetermined amount has not been reached, step S3 is performed.
In 5, the light emission is repeated while counting the number of times until a predetermined number of times or a predetermined integration amount is reached. If the number of times of light emission has not reached the predetermined number (N _IR0 ), the process proceeds to step S32. On the other hand, if the number of times of light emission has reached the predetermined number of times (N _{IR 0} ), step S
Move to 36.

On the other hand, in step S38, the flash device 14 emits light, and in step S39, counting of the number of times of light emission (N _ST ) is started. Next, step S40
It is determined whether or not the predetermined amount has been integrated. If a predetermined amount of integration has been performed, step S1
The process proceeds to step S5, but if the predetermined amount is not reached, in step S41, the number of times of light emission is counted and the process is repeated until the predetermined number of times or the predetermined integral amount is reached. If the number of times of light emission has not reached the predetermined number (N _ST0 ), the process proceeds to step S38. On the other hand, when the number of times of light emission has reached the predetermined number (N _ST0 ), the process _proceeds to step S36.

Then, in step S36, the time required for integration is determined using the integration time in step S12. Here, if it is determined that the scene is bright, the process proceeds to step S37, and the setting is such that the scene is focused. On the other hand, when it is determined that the scene is dark, the process proceeds to step S15.

This is a process in which it is determined that no projection light is detected, and it is considered that a bright scene has a high probability of being a landscape photograph. For example, in the case of a bright scene, such as when photographing a person, in many cases, an image with clear contrast should be obtained from the subject as shown in FIG. In such a case, the passive distance measurement of the integration in steps S11 to S15 is performed.
Focusing is possible.

If step S36 branches to "NO", or if the integration amount in the active mode (IRED or strobe projection distance measurement) reaches a predetermined amount in steps S34 and S40, The obtained data is read in step S15, and correlation and interpolation calculations are performed using the data.

However, if it is determined in step S24 that the reliability is low, the process proceeds to steps S26 to S27 in the active mode, and the light amount reflected from the subject in step S27 is used as the light amount. AF is performed. This is a distance detection method that utilizes the fact that a small amount of light from a distant subject and a large amount of light from a close subject are reflected and integrated, and depends on the reflectivity of the subject. Even when the reliability is low, an effective focusing distance can be detected.

In the case of a bright scene, the above steps S16 to S16
The effect of S18 makes it difficult to proceed to step S29, but this improves the reliability of distance measurement. That is, in the active mode, steady light is removed, so that in an extremely bright scene, an error in this case tends to affect the distance measurement. However, according to the present embodiment, such a scene is minimized in step S23. Since the distance measurement in the passive mode is easily performed by the calculation in S25, the above-described error can be prevented.

[0083]

As described above, according to the present invention,
It is possible to provide an auto-focus camera ranging device that can enjoy photographing without failure for subjects such as blue sky and scenery that many camera users enjoy photographing as well as ordinary portrait photographs.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a camera according to an embodiment of the present invention.

FIG. 2 is a diagram showing outputs of sensors R _{1 to} R ₆ on a sensor array 3a.

FIG. 3 is a diagram showing outputs of sensors L _{1 + S to} L _{6 + S} on a sensor array 3a.

FIG. 4 is a diagram illustrating a relationship between a difference between a right sensor R and a left sensor L and a shift amount of the FF sensor.

FIG. 5 is a graph in which the outputs of the respective sensors, for which the correlation calculation process has been completed, are shifted by a shift amount S and are then graphed in a form that allows easy comparison.

FIG. 6 is a flowchart illustrating an arithmetic processing operation by a CPU 10 according to an embodiment of the present invention.

FIG. 7 is a flowchart illustrating a distance measuring operation according to the embodiment of the present invention;

FIG. 8 is a flowchart illustrating a distance measuring operation according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a subject image with clear contrast.

FIG. 10 is a diagram illustrating an example of a subject image with low contrast.

[Explanation of symbols]

 1a, 1b light receiving lens, 2 subjects, 3a, 3b sensor array, 4 A / D converter, 5 arithmetic unit, 10 CPU, 11 focus lens group, 12 focusing control unit, 13 photometry unit, 14 flash light emitting device (strobe Device), 15 strobe control unit, 16 light emitting lens, 17 infrared light emitting diode (IRED), 18 driver, 19 steady light removal circuit, 20 release switch.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H011 AA01 2H051 AA01 BB07 BB09 BB20 CB20 CC12 CE06 CE18 CE20 CE28 DA02 DA03 DA22 DA32 DB03

Claims (4)

[Claims] 1. A pair of sensor arrays for receiving two images of a subject with parallax for distance detection, and comparing a difference between an output between the pair of sensor arrays and a predetermined value, Determining means for determining the level of reliability of distance detection based on the two images; brightness detecting means for detecting brightness of the subject image; and changing the predetermined value in accordance with an output of the brightness detecting means. A distance measuring device for a camera, comprising: 2. The method according to claim 1, wherein the changing unit changes the predetermined value to a direction in which the reliability determination is not easily determined to be low when the brightness is equal to or more than a predetermined value. Camera ranging device. 3. A light projecting means for repeatedly projecting pulsed distance measuring light onto a subject, an integrating means for integrating an output of the sensor array in synchronization with the repeated light projection, and an integration by the integrating means. Comparing means for comparing the level with a predetermined level; and when the reliability determination is determined to be low and the output of the brightness detecting means is equal to or more than a predetermined value, the number of the integration and the output of the comparing means 2. The camera distance measuring apparatus according to claim 1, further comprising: a determination unit that determines a distance to the subject. 4. A pair of sensor arrays for receiving two images of a subject with parallax for distance detection, and a sensor output difference in a specific area of at least one of the pair of sensor arrays. Determining means for comparing a predetermined value to determine the level of reliability of distance detection based on the two images; brightness detecting means for detecting the brightness of the subject image; and output of the brightness detecting means Changing means for changing the predetermined value according to the following.